The overall objective is new insight into integrative mechanisms at intermediate levels, between membrane mechanisms and higher nervous activity. The approach is comparative - using specially favorable species of lower vertebrates and invertebrates, including sharks, rays, electric fish, catfish and other fishes, octopus, and several mammals. Methods are primarily electrophysiological at the single and multiple unit level. Experiments fall into two groups. (1) Study of receptors and brain centers processing afferent input particularly acoustic, electric, and vestibular systems and other lateral line derivatives. New studies on elasmobranch olfaction and octopus vision have begun. (2) Interrelations in organized arrays such as nerve nets activity and EEG and evoked activity in higher and lower animals.